The invention relates to a device for repairing underground pipes, sewers or the like, that is, pipes which are generally laid in the ground and which consist of a material which tends to crack or break after many years of use, such as, for example, sewers. Moreover, the invention relates to uses of devices of this kind.
Devices of this kind are already familiar in an extremely diverse range of embodiments and allow the repair and reconstruction of damaged areas in the region of the walls of underground, pipe-shaped sewers, without the need to expose the damaged areas.
Damage to underground pipes such as sewers occurs particularly in the region of connections from individual buildings opening into a collective sewer. Devices for the repair of damaged areas of this kind, which provide an auxiliary body or subsidiary body branching off from an inflatable main body which fits into the sewer are already known, wherein the auxiliary body or subsidiary body is also inflatable and can be introduced at a connecting place in a sewer connection within which it can be inflated in order to supply the material required for repair and reconstructionxe2x80x94for example, a two-component synthetic material mixturexe2x80x94through the main body to the damaged areas in a targeted manner.
A two-component synthetic material is used by preference as the repair medium, of which the two components are not combined until immediately before reaching the damaged area to be reconstructed, so that these can react with one another for a short period thereby hardening in the vicinity of the damaged area and the surrounding ground.
The devices already known for repair and reconstruction work of this kind are indeed usable and suitable in practice, however, they are associated with relatively high manufacturing and operating costs.
The invention is based on the object of providing a simplified device which is simpler to operate for the repair of imderground sewers or the like; which is also less expensive to manufacture; but which avoids the need for limitations of efficiency and usefulness.
In particular, the invention is intended to provide a device which is suitable for the repair of underground sewers in the region of connections to buildings.
Moreover, according to the invention, special uses of the device according to the invention are specified.
The device according to the invention provides a cylindrical, hollow body with a casing capable of elastic expansion which serves as the outer wall. The elastically expandable casing serving as the outer wall guarantees that the device can fit tightly inside a pipe-shaped sewer which is to be repaired. This avoids point-contact of the device and the associated overloading of the sewer. Furthermore, a device with a cylindrical cross-section provides sufficient space to accommodate further means, for example, a bellows which can be moved inward and outward in a lateral direction.
With one advantageous embodiment of the device according to the invention, it is possible to supply the synthetic material used for repair and reconstruction, especially a two-component material, to the relevant repair site in such a manner that this material cannot penetrate into areas covered by portions of the device which are expanded in the operating condition.
A collar or curved plate made, for example, from a rigid material and provided for this purpose is preferably fitted into the expandable hollow body and therefore follows the expanding movements of the hollow body, but even when the hollow body is expanded, the collar or curved plate lies in such a manner that a hollow cavity of the same thickness as the wall of the expandable casing of the main body of the device remains between this collar or plate and the relevant wall of the sewer to be repaired, into which repair material can penetrate and harden without this hardened material causing a disturbance after the device has been deflated or depressurised and removed from the repair area.
The plate-shaped collar provided in the elastically expandable hollow body of the device is curved in a cylindrical manner and adapted approximately to the diameter of the relevant sewers to be repaired and reconstructed. These diameters may, however, vary in certain regions, so that the device according to the invention can be used within a given bandwidth for sewers of different interior diameters, and similarly for the repair of pipe connections such as building connections of different diameters.
The elastically expandable bellows, which can be introduced into a sewer connection and inflated, can be completely retracted into the main body of the device so that it does not provide an obstacle when the device is being moved within the sewer to be repaired and, indeed, need not be used, if the device is to be used for repairing a sewer outside the region of a pipe connection.
Moreover, the cylindrical bellows, at the outer end of which a television camera is preferably provided, can be moved to different depths within a sewer connection, as required for the relevant repair or reconstruction.
In the device according to the invention, the cylindrical hollow body advantageously provides a casing surface of adjustable diameter. Accordingly, the hollow body can be adapted for different internal sewer diameters while retaining its cylindrical shape.
Cost-intensive structural changes are therefore not required to adapt the device for different sewer diameters.
Means are provided for enlarging the diameter of the hollow body. For example, this can be achieved with a mechanical, hydraulic or pneumatic device.
The cylindrical hollow body of the device according to the invention is advantageously a cylindrically curved plate, wherein preferably two edges of the plate overlap one another. This results in a cylindrical hollow body which is particularly inexpensive to manufacture. Because the edges are in contact with one another in an overlapping manner, it retains its cylindrical shape even if the diameter of the hollow body is altered. For example, the original diameter of the hollow body may be 33 cm. This can be expanded by way of adaptation to different internal sewer diameters from 35 to 42 cm. The device can therefore be used in a flexible manner without the replacement of parts.
The diameter of the casing of the cylindrical hollow body of the device according to the invention is advantageously adjusted by means of two bellows expandable with compressed air and located close to the end faces of the cylindrical hollow body. In this case, the elastic casing exerts a restoring force on the previously implemented adjustments. Attachment of the bellows close to the end faces of the cylindrical hollow body means that the casing of the cylindrical hollow body is pressed more tightly against the internal walls of the sewer at these places and exerts a more powerful sealing effect there than in the region of the casing between the bellows. Accordingly, repair material can also be pressed into the region between the casing and the internal wall of the sewer, which, with reference to the hollow cylinder, is located between the surfaces of the casing pressed against the internal wall of the sewer by the bellows.
When using an appropriate liquid repair material, a damaged, cracked sewer pipe can be repaired not only at the position on the casing surface of the cylindrical hollow cylinder from which the repair material is dispensed, but also covering a larger area over the entire circumferential casing surface of the cylindrical hollow body located between the bellows. In former times, it was conventional to break through sewer pipes with a pointed implement to provide an opening for connections to buildings. This caused hair-line cracks and resulting larger-scale damage to the sewer wall; however, these can also be repaired by means of the above-mentioned large-area repair measures.
The cylindrical hollow body of the device according to the invention advantageously contains one or more channel-like openings extending in an axial direction. This means that when the cylindrical hollow body is introduced into a sewer, the effluent contained in the sewer is not blocked and/or the sewage flow is not impeded.
The device according to the invention advantageously provides several hoses for the supply of a repair material consisting of several components and a mixer for mixing the components. In this manner, one component of the repair material can be supplied by each of the hoses. If a repair material is used which does not harden until all components come into contact with one another, separate supply in several hoses avoids hardening in the supply means and prevents the time-consuming salvage, dismantling and cleaning of the device before each repair operation. In particular, this can be achieved by xe2x80x9ccleaningxe2x80x9d the mixer and the parts of the device which have been in contact with the mixed, multiple-component repair material by rinsing briefly with only one component of the repair material after each mixing and repair procedure.
In the device according to the invention, the inflatable, elastically expandable, cylindrical bellows which can, if required, be introduced into a pipe connection of the sewer, advantageously allows a depth of penetration into the pipe connection of at least 50 cm. This means that any damage which extends beyond the connecting point of the pipe connection into the connecting pipe itself can be repaired. In this manner, it is possible, for example, to repair a first or even a second leaking connection sleeve of the pipe connection.
The device according to the invention advantageously provides one or more video cameras for monitoring and control. For example, one camera is fitted into the tip of the insertable, inflatable, elastically extendable, cylindrical bellows in order to position this in front of a pipe connection and to insert it therein. For example, further cameras may be attached at the end faces of a hollow cylinder in such a manner that the entire device including an ongoing reconstruction measure can be monitored. An ongoing repair process can be interrupted as soon as an excessive flow of repair material is observed beyond the actual repair site and the device.
Close to the end faces of the cylindrical hollow body, the device according to the invention advantageously contains two bladders and a compressed air line leading towards these bladders. Furthermore, a device may be provided for measuring a reduction in pressure in the region between the inflated bladders.
A further compressed air line, which opens between the two bladders towards the exterior of the cylindrical hollow body may be provided to measure the reduction in pressure. When compressed air is supplied, the device for measuring a reduction in pressure can determine whether the portion of the sewer between the two bladders is leaking. Accordingly, it is possible to carry out a leak assessment over the approximate length of the device. Furthermore, a check can be carried out immediately after the repair has been completed without needing to salvage the device and replace it with special pressure measuring equipment.
According to the invention, a resin consisting of two components is used in order to repair a sewer which requires reconstruction. In this context, the components are selected in such a manner that they do not tend to harden when they are kept separately. However, when these components come into contact with one another and are preferably mixed, a rapid hardening reaction of the mixture takes place. This prevents hardening within the device. Since water is avoided as a solvent, a repair can be carried out even in very damp, aqueous surroundings, for example, in the case of a sewage pipe located in the region of the ground water, without the risk that the repair material will be washed away, as might occur, for example, when using mortar.
By preference, a resin is used which is a thin liquid before hardening and which does not tend towards foaming during mixing and/or hardening, for example, a silicate resin. The use of a resin which does not tend to foam prevents any uncontrolled expansion of the repair material, for example, into effluent-carrying regions of the sewer. A resin which is a thin liquid before hardening can readily flow around the casing surface of the device during reconstruction and therefore allows the repair of a sewer over a large area. Moreover, it also readily penetrates through any cracks existing in the sewer to be renovated and into the surrounding ground, thereby improving the bedding of the sewer after hardening in addition to the actual reconstruction of the sewer.
The device according to the invention is used, for example, for the reconstruction of damaged sewer connections to buildings. It can also been used to cut off or separate from the public sewage network building connections which have been cancelled or taken out of operation. When the device according to the invention is used, the costintensive and time-consuming digging up of road and pavement surfaces is not necessary. Furthermore, the disadvantage of inadequate durability associated with closures based on inflated pipe-sealing cushions is avoided, because the closure is achieved by means of a hardening repair material.
The device according to the invention is used for the repair of several places in a sewer without the device having to be salvaged from the sewer between individual repair operations. For example, the use of a multiple-component repair material with several supply lines avoids the salvage, cleaning and possibly dismantling of the device in order to make it ready for a subsequent repair operation.